Occasional Night Shift Work Linked to Increased Risk of Heart Disease

A new study shows that working night shifts in conjunction with day shifts can slightly affect worker's health resulting to a higher risk of developing coronary heart disease compared to those who do not have rotating shifts.

The study, published in the journal JAMA, reveals that people who work at least three night shifts every month are more likely to develop cardiovascular problems than those who only work during daytime.

For the study, the researchers analyzed the 24 years worth of collected data from more than 189,000 women working as nurses. About 40 percent of the participants were enrolled in the Nurse's Health Study (NHS) while the remaining nurses were participating in the NHS 2. NHS 1 began in 1988 followed by NHS 2 in 1989.

The nurses participating in the research entered the study between the ages of 25 and 55. They also show no symptoms or signs of coronary heart diseases.

According to the report from CBS News, the participants were asked about their lifetime exposure to rotating night shifts, which was defined as working three or more night shifts in a month, in addition to their day and evening shifts. Questions about their lifestyles, such as their diet, exercise and smoking habits, were also reported to the researchers.

Over the course of 24 years, over 10,000 of newly developed cases of coronary heart disease were observed. Upon further analysis of the data, researchers discovered that nurses who have rotating night shift for more than 10 years have 15 to 18 percent increase risk of developing coronary heart disease compared to those who did not.

The researchers also noted a decrease in the risk of developing heart disease when the nurses have stopped working in rotating shifts or have retires.

There is still no causal relationship that can be formed in the study, but the researchers believe that rotating shifts can disrupt the circadian rhythm resulting to sleep deprivation.

Previous research suggests that rotating shifts resulting to the disruption of the normal sleep pattern can both affect men and women, but it tends to have more detrimental effect on women.